Injection stretch blow molded articles and random copolymers for use therein

ABSTRACT

Injection stretch blow molded (ISBM) articles and methods of forming the same are described herein. The ISBM articles generally include a metallocene random propylene-based copolymer.

FIELD

Embodiments of the present invention generally relate to polymersadapted for use in injection stretch blow molding. In particular,embodiments of the invention relate to metallocene randompropylene-based copolymers adapted for use in injection stretch blowmolding.

BACKGROUND

Attempts have been made to utilize propylene based random copolymers forinjection stretch blow molding (ISBM) applications. However, in order toachieve high clarity, the ISBM grade polypropylene resins are usuallyclarified by sorbitol based clarifiers, which are not desirable formedical applications. In addition, the polypropylene (PP) ISBM processis more demanding than polyethylene terephthalate (PET) ISBM process,especially during the re-heating stage.

Therefore, a need exists for developing resins which can be more easilyreheated during the ISBM process and will result in ISBM articlesexhibiting high clarity without the use of undesirable clarifiers.

SUMMARY

Embodiments of the present invention include injection stretch blowmolded (ISBM) articles. The ISBM articles generally include ametallocene random propylene-based copolymer.

Embodiments of the invention further include injection stretch blowmolded (ISBM) medical and cosmetic packaging and flexible containersthat include a metallocene random propylene-based copolymer whichexhibits a melt flow rate of from about 1 dg/min to about 40 dg/min., amelting point less than 130° C., a haze of less than 5%, and a gloss at45° greater than 75%.

Embodiments further include methods of forming injection stretch blowmolded (ISBM) articles which include providing a metallocene randompropylene-based copolymer, injection molding the propylene-based impactcopolymer into a preform and stretch-blowing the preform into anarticle.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 illustrates graphically the maximum top load strength of ISBMarticles.

DETAILED DESCRIPTION Introduction and Definitions

A detailed description will now be provided. Each of the appended claimsdefines a separate invention, which for infringement purposes isrecognized as including equivalents to the various elements orlimitations specified in the claims. Depending on the context, allreferences below to the “invention” may in some cases refer to certainspecific embodiments only. In other cases it will be recognized thatreferences to the “invention” will refer to subject matter recited inone or more, but not necessarily all, of the claims. Each of theinventions will now be described in greater detail below, includingspecific embodiments, versions and examples, but the inventions are notlimited to these embodiments, versions or examples, which are includedto enable a person having ordinary skill in the art to make and use theinventions when the information in this patent is combined withavailable information and technology.

Various terms as used herein are shown below. To the extent a term usedin a claim is not defined below, it should be given the broadestdefinition persons in the pertinent art have given that term asreflected in printed publications and issued patents at the time offiling. Further, unless otherwise specified, all compounds describedherein may be substituted or unsubstituted and the listing of compoundsincludes derivatives thereof.

Various ranges are further recited below. It should be recognized thatunless stated otherwise, it is intended that the endpoints are to beinterchangeable. Further, any point within that range is contemplated asbeing disclosed herein.

As used herein, “opaque” means an article is impenetrable to visiblelight that is, an opaque object prevents transmission of essentially allvisible light. “Transparent” means essentially all visible light passesthrough the article. The term “semi-opaque” means some, but not all,visible light passes through the article.

As used herein, “haptics” refers to the sensations produced by skincontact with foreign material, such as cloth or plastic. Therefore,“good haptics”, as used herein, refers to the feel of a bottle whenheld, such as the softness of a bottle.

Catalyst Systems

Catalyst systems useful for polymerizing olefin monomers include anycatalyst system known to one skilled in the art. For example, thecatalyst system may include metallocene catalyst systems, single sitecatalyst systems, Ziegler-Natta catalyst systems or combinationsthereof, for example. As is known in the art, the catalysts may beactivated for subsequent polymerization and may or may not be associatedwith a support material. A brief discussion of such catalyst systems isincluded below, but is in no way intended to limit the scope of theinvention to such catalysts.

For example, Ziegler-Natta catalyst systems are generally formed fromthe combination of a metal component (e.g., a catalyst) with one or moreadditional components, such as a catalyst support, a cocatalyst and/orone or more electron donors, for example.

Metallocene catalysts may be characterized generally as coordinationcompounds incorporating one or more cyclopentadienyl (Cp) groups (whichmay be substituted or unsubstituted, each substitution being the same ordifferent) coordinated with a transition metal through π bonding. Thesubstituent groups on Cp may be linear, branched or cyclic hydrocarbylradicals, for example. The cyclic hydrocarbyl radicals may further formother contiguous ring structures, including indenyl, azulenyl andfluorenyl groups, for example. These contiguous ring structures may alsobe substituted or unsubstituted by hydrocarbyl radicals, such as C₁ toC₂₀ hydrocarbyl radicals, for example.

Polymerization Processes

As indicated elsewhere herein, catalyst systems are used to formpolyolefin compositions. Once the catalyst system is prepared, asdescribed above and/or as known to one skilled in the art, a variety ofprocesses may be carried out using that composition. The equipment,process conditions, reactants, additives and other materials used inpolymerization processes will vary in a given process, depending on thedesired composition and properties of the polymer being formed. Suchprocesses may include solution phase, gas phase, slurry phase, bulkphase, high pressure processes or combinations thereof, for example.(See, U.S. Pat. No. 5,525,678; U.S. Pat. No. 6,420,580; U.S. Pat. No.6,380,328; U.S. Pat. No. 6,359,072; U.S. Pat. No. 6,346,586; U.S. Pat.No. 6,340,730; U.S. Pat. No. 6,339,134; U.S. Pat. No. 6,300,436; U.S.Pat. No. 6,274,684; U.S. Pat. No. 6,271,323; U.S. Pat. No. 6,248,845;U.S. Pat. No. 6,245,868; U.S. Pat. No. 6,245,705; U.S. Pat. No.6,242,545; U.S. Pat. No. 6,211,105; U.S. Pat. No. 6,207,606; U.S. Pat.No. 6,180,735 and U.S. Pat. No. 6,147,173, which are incorporated byreference herein.)

In certain embodiments, the processes described above generally includepolymerizing one or more olefin monomers to form polymers. The olefinmonomers may include C₂ to C₃₀ olefin monomers, or C₂ to C₁₂ olefinmonomers (e.g. ethylene, propylene, butene, pentene, methylpentene,hexene, octene and decene), for example. The monomers may includeolefinic unsaturated monomers, C₄ to C₁₈ diolefins, conjugated ornonconjugated dienes, polyenes, vinyl monomers and cyclic olefins, forexample. Non-limiting examples of other monomers may include norbornene,nobornadiene, isobutylene, isoprene, vinylbenzocyclobutane, sytrene,alkyl substituted styrene, ethylidene norbornene, dicyclopentadiene andcyclopentene, for example. The formed polymer may include homopolymers,copolymers or terpolymers, for example.

Examples of solution processes are described in U.S. Pat. No. 4,271,060,U.S. Pat. No. 5,001,205, U.S. Pat. No. 5,236,998 and U.S. Pat. No.5,589,555, which are incorporated by reference herein.

One example of a gas phase polymerization process includes a continuouscycle system, wherein a cycling gas stream (otherwise known as a recyclestream or fluidizing medium) is heated in a reactor by heat ofpolymerization. The heat is removed from the cycling gas stream inanother part of the cycle by a cooling system external to the reactor.The cycling gas stream containing one or more monomers may becontinuously cycled through a fluidized bed in the presence of acatalyst under reactive conditions. The cycling gas stream is generallywithdrawn from the fluidized bed and recycled back into the reactor.Simultaneously, polymer product may be withdrawn from the reactor andfresh monomer may be added to replace the polymerized monomer. Thereactor pressure in a gas phase process may vary from about 100 psig toabout 500 psig, or from about 200 psig to about 400 psig or from about250 psig to about 350 psig, for example. The reactor temperature in agas phase process may vary from about 30° C. to about 120° C., or fromabout 60° C. to about 115° C., or from about 70° C. to about 110° C. orfrom about 70° C. to about 95° C., for example. (See, for example, U.S.Pat. No. 4,543,399; U.S. Pat. No. 4,588,790; U.S. Pat. No. 5,028,670;U.S. Pat. No. 5,317,036; U.S. Pat. No. 5,352,749; U.S. Pat. No.5,405,922; U.S. Pat. No. 5,436,304; U.S. Pat. No. 5,456,471; U.S. Pat.No. 5,462,999; U.S. Pat. No. 5,616,661; U.S. Pat. No. 5,627,242; U.S.Pat. No. 5,665,818; U.S. Pat. No 5,677,375 and U.S. Pat. No. 5,668,228,which are incorporated by reference herein.)

Slurry phase processes generally include forming a suspension of solid,particulate polymer in a liquid polymerization medium, to which monomersand optionally hydrogen, along with catalyst, are added. The suspension(which may include diluents) may be intermittently or continuouslyremoved from the reactor where the volatile components can be separatedfrom the polymer and recycled, optionally after a distillation, to thereactor. The liquefied diluent employed in the polymerization medium mayinclude a C₃ to C₇ alkane (e.g., hexane or isobutane), for example. Themedium employed is generally liquid under the conditions ofpolymerization and relatively inert. A bulk phase process is similar tothat of a slurry process with the exception that the liquid medium isalso the reactant (e.g., monomer) in a bulk phase process. However, aprocess may be a bulk process, a slurry process or a bulk slurryprocess, for example.

In an embodiment, a slurry process or a bulk process may be carried outcontinuously in one or more loop reactors. The catalyst, as slurry or asa dry free flowing powder, may be injected regularly to the reactorloop, which can itself be filled with circulating slurry of growingpolymer particles in a diluent, for example. Optionally, hydrogen may beadded to the process, such as for molecular weight control of theresultant polymer. The loop reactor may be maintained at a pressure offrom about 27 bar to about 50 bar or from about 35 bar to about 45 barand a temperature of from about 38° C. to about 121° C., for example.Reaction heat may be removed through the loop wall via any method knownto one skilled in the art, such as via a double-jacketed pipe or heatexchanger, for example.

In an embodiment, a process for producing a copolymer may be carried outthat includes polymerizing in a linear liquid slurry or gas phasereactor in the presence of a polymerization catalyst that involvesinjecting at least one olefin comonomer at more than one point along thelength of the reactor. (See, for example, U.S. Pat. No. 7,053,163 whichis incorporated by reference herein.)

Alternatively, other types of polymerization processes may be used, suchas stirred reactors in series, parallel or combinations thereof, forexample. Upon removal from the reactor, the polymer may be passed to apolymer recovery system for further processing, such as addition ofadditives and/or extrusion, for example.

Polymer Product

The polymers (and blends thereof) formed via the processes describedherein may include, but are not limited to, linear low densitypolyethylene, elastomers, plastomers, high density polyethylenes, lowdensity polyethylenes, medium density polyethylenes, polypropylene andpolypropylene copolymers, for example.

Unless otherwise designated herein, all testing methods are the currentmethods at the time of filing.

In one or more embodiments, the polymers include propylene basedpolymers. As used herein, the term “propylene based” is usedinterchangeably with the terms “propylene polymer” or “polypropylene”and refers to a polymer having at least about 50 wt. %, or at leastabout 70 wt. %, or at least about 75 wt. %, or at least about 80 wt. %,or at least about 85 wt. % or at least about 90 wt. % polypropylenerelative to the total weight of polymer, for example

The propylene based polymers may have a molecular weight distribution(M_(n)/M_(w)) of from about 1.0 to about 20, or fiom about 1.5 to about15 or from about 2 to about 12, for example.

In one embodiment, the propylene polymer has a microtacticity of fromabout 89% to about 99%, for example.

In one embodiment, propylene based polymers may have a recrystallizationtemperature (T_(c)) (as measured by DSC) range of 70-120° C., or from 80to 110° C., or from 85 to 100° C.

In one embodiment, propylene based polymers may have a molecular weight(M_(w)) range of 150,000 to 230,000, or from 170,000 to 210,000, or from180,000 to 200,000 (as measured by gel permeation chromatography).

The propylene based polymers may have a melting point (T_(m)) (asmeasured by DSC) of at least about 105° C., or from about 115° C. toabout 175° C., for example.

The propylene based polymers may include about 15 wt. % or less, orabout 12 wt. % or less, or about 10 wt. % or less, or about 6 wt. % orless, or about 5 wt. % or less, or about 4 wt. % or less of xylenesoluble materials (XS), for example (as measured by ASTM D5492-06).

The propylene based polymers may have a melt flow rate (MFR) (asmeasured by ASTM D-1238) of from about 0.01 dg/min to about 1000dg/min., or from about 0.01 dg/min. to about 100 dg/min., for example.The propylene based random copolymers may exhibit a melt flow rate of atleast about 1 dg./min., or from about 5 dg./min. to about 30 dg./min. orfrom about 10 dg./min. to about 20 dg./min., for example.

In one or more embodiments, the propylene based polymers have a low meltflow rate (MFR). As used herein, the term low melt flow rate refers to apolymer having a MFR of less than about 10 dg/min., or less than about 6dg/min., or less than about 2.6 dg/min., or from about 0.5 dg/min. toless than 10 dg/min. or from about 0.5 dg/min. to about 6 dg/min., forexample.

In one or more embodiments, the polymers include propylene based randomcopolymers. Unless otherwise specified, the term “propylene based randomcopolymer” refers to those copolymers composed primarily of propyleneand an amount of at least one comonomer, wherein the polymer includes atleast about 0.5 wt. %, or at least about 0.8 wt. %, or at least about 2wt. %, or from about 0.5 wt. % to about 5.0 wt. %, or fiom about 0.6 wt.% to about 1.0 wt. % comonomer relative to the total weight of polymer,for example. The comonomers may be selected from C₂ to C₁₀ alkenes. Forexample, the comonomers may be selected from ethylene, propylene,1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene,4-methyl-1-pentene and combinations thereof. In one specific embodiment,the comonomer includes ethylene. Further, the term “random copolymer”refers to a copolymer formed of macromolecules in which the probabilityof finding a given monomeric unit at any given site in the chain isindependent of the nature of the adjacent units.

In one embodiment, additives may also be included in the finalcomposition. The additives may contact the polymer by any method knownto one skilled in the art. For example, the additives may contact thepolymer prior to extrusion (within the polymerization process) or withinthe extruder, for example. In one embodiment, the additives contact thepolymer independently. In another embodiment, the additives arecontacted with one another prior to contacting the polymer. In oneembodiment, the contact includes blending, such as mechanical blending,for example.

Product Application

The polymers and blends thereof are useful in applications known to oneskilled in the art, such as forming operations (e.g., film, sheet, pipeand fiber extrusion and co-extrusion as well as blow molding, injectionmolding and rotary molding). Films include blown, oriented or cast filmsformed by extrusion or co-extrusion or by lamination useful as shrinkfilm, cling film, stretch film, sealing films, oriented films, snackpackaging, heavy duty bags, grocery sacks, baked and frozen foodpackaging, medical packaging, industrial liners, and membranes, forexample, in food-contact and non-food contact application. Fibersinclude slit-films, monofilaments, melt spinning, solution spinning andmelt blown fiber operations for use in woven or non-woven form to makesacks, bags, rope, twine, carpet backing, carpet yarns, filters, diaperfabrics, medical garments and geotextiles, for example. Extrudedarticles include medical tubing, wire and cable coatings, sheet,thermoformed sheet, geomembranes and pond liners, for example. Moldedarticles include single and multi-layered constructions in the form ofbottles, tanks, large hollow articles, rigid food containers and toys,for example.

In one or more embodiments, the polymers are utilized in injectionstretch blow molding (ISBM) processes to form ISBM articles. The ISBMarticles may include thin-walled bottles and other types of containers,for example. The ISBM articles may be formed by any suitable process.For example, ISBM processes may include injecting the polymer into apreform and subsequently stretch-blowing the preform into the desiredfinal form, for example.

In one or more embodiments, the metallocene random propylene basedcopolymers, as described above, are utilized to form the ISBM articles.

In one or more embodiments, the ISBM articles are medical grade orcosmetic grade articles. In one or more embodiments, the ISBM articlesare bottles. Such cosmetic packaging could include products such asviscose lotions, pastes, and drops, for example.

The articles formed from the metallocene random propylene-basedcopolymers exhibit high clarity, article flexibility, and good haptics,without the use of clarifiers.

In one or more embodiments, the ISBM articles exhibit high clarity. Forexample, the ISBM articles may exhibit a haze of less than 15%, or lessthan 10%, or less than 5%, or less than 2% (as measured by ASTM D1003).

In one or more embodiments, the ISBM articles exhibit high gloss. Forexample, the ISBM articles may exhibit a gloss at 450 of greater than50%, or greater than 65%, or greater than 75% (as measured by ASTMD2457).

In one or more embodiments, the ISBM (e.g., 23 g) articles may exhibit amaximum top load, as measured by ASTM D2659, of at least about 70 N, orat least about 100 N or at least about 110 N, for example.

In one or more embodiments, the article is stretch-blown at a productionrate of at least about 500 articles per hour per cavity, or from 750 to2000 articles per hour per cavity, or from 1000 to 1500 articles perhour per cavity.

EXAMPLES

The mRCP Resin refers to TOTAL Petrochemicals EOD02-15, which is ametallocene random propylene-based copolymer having a melting point ofapproximately 119° C. and is commercially available from TOTALPetrochemicals USA, Inc.

Comparative Resin refers to TOTAL Petrochemicals 7525MZ, which is apropylene based random copolymer having a MFR of 10 dg/min., and whichis commercially available from TOTAL Petrochemicals USA, Inc.

The polymer samples were injection stretch blow molded (ISBM) intobottles. The bottles were then tested for top load and opticalproperties.

The preforms were prepared as follows. The mRCP Resin was injectionmolded into 23 g preforms on the Netstal injection molder under theinjection molding conditions listed in Table 1. The preforms wereconditioned at room temperature for at least 24 hours before they werestretch-blow-molded into bottles on ADS G62 linear injection stretchblow molder.

TABLE 1 Preform injection-molding condition. Resin mRCP ResinComparative Resin Preform Weight 23 g 23 g Barrel temperature (° C.) 230250 Hot runner temperature (° C.) 230 250 Mold temperature (static/move)10/10 10/10 (° C.) Injection speed (mm/s) 5 5 Cooling time (s) 15 15Hold time (s) 15 4 Cycle time (s) ca. 38.8 ca. 26.6

Because of the mRCP Resin's low melting point, it was injection moldedat a relatively low barrel and hot runner temperature setting of 230° C.

The mRCP Resin preforms were blow molded into bottles without any issue(reject rate <1%) at both 1000 and 1500 bottles/hour/cavity. During theevaluation, it was observed that the mRCP Resin preforms could be blowmolded using a much lower heating profile as expected. In addition, thepreforms required a much lower blow pressure than regular isotacticpolypropylene resins. The molded bottles were very clear but felt soft.In order to estimate the energy saving for processing the mRCP Resin, aComparative Resin was used for comparison.

It should be noted that there are numerous combinations of heateroutputs that can lead to a similar heating effect and a low reject rate(<1%). In order to have a consistent comparison, it is necessary to usea similar type of temperature profile (similar distribution of heatingpower along the preform). Thus, the temperature profile optimization onthe mRCP Resin was started from the pre-optimized profile for theComparative Resin. By gradually reducing the temperature settings onindividual heaters, an optimized temperature profile for the mRCP Resinwas obtained. Note that the optimized temperature profile for eachmaterial requires that the resulting bottles exhibit uniform wallthickness and minimal defects based on visual inspection. The optimizedtemperature profiles for the two preforms are displayed in Table 2.

TABLE 2 Optimized temperature profile for Comparative Resin and mRCPResin (1000 bottles/h/cavity). Comparative Resin mRCP Resin Lamps Oven10 Oven 20 Oven 10 Oven 20 L1 (W) 1550 1250 1400 1200 L2 (W) 1350 900500 400 L3 (W) 350 350 300 200 L4 (W) 450 350 500 400 L5 (W) 1350 600700 350 L6 (W) 250 250 400 300 L7 (W) 150 150 400 300 Total (W) 54503850 4200 3150 Good bottle rate >99% >99% Energy saving —  21% BlowPressure 26 8 (bar)

The results showed that the heat energy required for blowing the mRCPResin was approximately 21% lower than that for the Comparative Resin.Moreover, the MRCP Resin preforms were successfully blow molded intobottles with an extremely low blow pressure. After temperature profileoptimization, the blow pressure was reduced gradually to 8 bar, which isthe lower limit of the regulator on the ISBM high pressure gas line. ThemRCP Resin bottles were successfully blow molded at 8 bar without anyissue. It was also attempted to blow the bottles with the pre-blowpressure (6 bar) only. Again, bottles were successfully formed. However,using only the 6 bar pre-blow pressure the engraving on the bottle wasnot very clear.

The mRCP Resin bottles blow molded under the conditions listed in Table2 were tested for top load and clarity. The results) provided in Table3, and illustrated in FIG. 1 for maximum top load, showed that the topload strength of the mRCP Resin bottles was lower than the ComparativeResin bottles. But the bottles were highly flexible and had a softtouch, which would be beneficial in certain applications. In addition,the bottles exhibited high gloss and low haze, without the need of anyclarifiers.

TABLE 3 Mechanical and optical properties of 23 g mRCP Resin andComparative Resin bottles. Bumper compression at Maximum Top 0.50 inchload (N) deflection (N) Gloss (%) Haze (%) mRCP 112.9 ± 4.4 65.8 ± 3.477.4 ± 5.6 1.5 ± 0.4 Resin Comparative 151.3 ± 5.9 78.9 ± 5.6 81.6 ± 3.01.1 ± 0.1 Resin Note: the optical properties shown here were measured atbottle sidewall. The Comparative Resin is clarified with a sorbitolbased clarifier.

The mRCP Resin demonstrated several beneficial attributes in ISBMapplications. Because of its low melting point, the mRCP Resin wassuccessfully blow molded into bottles with a low heat profile(approximately 20% lower than that for the Comparative Resin) andextremely low blow pressure (approximately 70% lower than that for theComparative Resin). The mRCP Resin bottles possess sufficient top loadstrength, and the bottles exhibit good flexibility. In addition,although mRCP Resin contains no clarifier, the mRCP Resin bottlesexhibit high clarity. The ability to avoid the use of sorbitol basedclarifiers in conjunction with the extremely low extractable content ofmetallocene polypropylene would be beneficial for such applications asmedical and cosmetic packaging.

While various embodiments have been shown and described, modificationsthereof can be made by one skilled in the art without departing from thespirit and teachings of the disclosure. The embodiments described hereinare exemplary only, and are not intended to be limiting. Many variationsand modifications of the embodiments disclosed herein are possible andare within the scope of the disclosure. Where numerical ranges orlimitations are expressly stated, such express ranges or limitationsshould be understood to include iterative ranges or limitations of likemagnitude falling within the expressly stated ranges or limitations(e.g., from about 1 to about 10 includes, 2, 3, 4, etc.; greater than0.10 includes 0.11, 0.12, 0.13, etc.). Use of the term “optionally” withrespect to any element of a claim is intended to mean that the subjectelement is required, or alternatively, is not required. Bothalternatives are intended to be within the scope of the claim. Use ofbroader terms such as comprises, includes, having, etc. should beunderstood to provide support for narrower terms such as consisting of,consisting essentially of, comprised substantially of, etc.

Accordingly, the scope of protection is not limited by the descriptionset out above but is only limited by the claims which follow, that scopeincluding all equivalents of the subject matter of the claims. Each andevery claim is incorporated into the specification as an embodiment ofthe present disclosure. Thus, the claims are a further description andare an addition to the embodiments disclosed herein. The discussion of areference herein is not an admission that it is prior art to the presentdisclosure, especially any reference that may have a publication dateafter the priority date of this application. The disclosures of allpatents, patent applications, and publications cited herein are herebyincorporated by reference, to the extent that they provide exemplary,procedural or other details supplementary to those set forth herein.

1. An injection stretch blow molded (ISBM) article comprising: ametallocene random propylene-based copolymer in the absence of aclarifier.
 2. The ISBM article of claim 1, wherein the metallocenerandom propylene-based copolymer exhibits a melt flow rate of from about1 dg/min. to about 40 dg/min.
 3. The ISBM article of claim 1, whereinthe article has a haze of less than 5%.
 4. The ISBM article of claim 1,wherein the article has a gloss at 45° of greater than 75%.
 5. The ISBMarticle of claim 1, wherein the article is a medical packagingcontainer.
 6. The ISBM article of claim 1, wherein the article iscosmetic packaging.
 7. The ISBM article of claim 1, wherein the articleexhibits a maximum top load of at least about 100 N at a weight of 23 g.8. An injection stretch blow molded (ISBM) package or containercomprising: a metallocene random propylene-based copolymer exhibiting amelt flow rate of from about 1 dg/min to about 40 dg/min. and a meltingpoint of from 105 to 130° C.; a top load of at least 100 N at a weightof 23 g; a haze of less than 5%; and a gloss at 45° of greater than 75%.9. A method of forming an injection stretch blow molded (ISBM) articlecomprising: providing a metallocene random propylene-based copolymer;injection molding the metallocene random propylene-based copolymer intoa preform; and stretch-blowing the preform into an article.
 10. Themethod of claim 9, wherein the article is stretch-blown at a productionrate of at least about 1000 articles per hour per cavity.
 11. The methodof claim 10, wherein the article is stretch-blown at a production rateof at least about 1500 articles per hour per cavity.
 12. The method ofclaim 9, wherein the metallocene random propylene-based copolymerexhibits a melt flow rate of from about 1 dg/min. to about 40 dg/min.and a melting point of from 105 to 130° C.
 13. The method of claim 9,wherein the article is selected from the group consisting of medicalpackaging or cosmetic packaging.
 14. The method of claim 9, wherein thearticle has good hapties.
 15. The method of claim 9, wherein thestretch-blowing is performed at a pressure of 8 bar.
 16. The method ofclaim 9, wherein the stretch-blowing requires a heat energy of at least20% less than the heat energy required for similar stretch-blowing of anon-metallocene random propylene-based copolymer.